To provide a method for producing a power transmitting belt which controls noise and vibration during back traveling.

The method for producing the power transmitting belt has a process (a) in which a sewing machine-jointed cylindrical duck is manufactured by using sewing machine threads formed from water soluble fibers, a process (b) for forming a vulcanized sleeve on which the cylindrical duck is laminated, and a process (c) in which water is contacted with a joint part to dissolve/remove the water soluble fibers exposed to at least the surface. A V-ribed belt 1 obtained by the method is composed of a stretch part made of a duck 3 having a joint part 6, an adhesive layer 2 in which a core wire 3 made of a code is embedded, and a compression part 4 which is an elastomer layer on its lower side. The compression part 4 has trapezoidal ribs having approximately triangle cross sections extending in the belt longitudinal direction.